Method and apparatus for electrical printing



Nov. 4, 1958 E- M KANE 2,858,633

METHOD AND APPARATUS FOR ELECTRICAL PRINTING Filed Jan. 7. 1954 INVENTORERNEST M. KANE ATTORNEYS United States Patent METHOD AND APPARATUS FORELECTRICAL PRINTING Ernest M. Kane, Oxnard, Calif.

Application January 7, 1954, Serial No. 402,832

9 Claims. (Cl. 41-37) (Granted under Title 35, U. S. Code (1952), sec.266) The invention described herein may be manufactured and used by orfor the Government of the United States of America for governmentalpurposes without the payment of any royalties thereon or therefor.

The present invention relates to a method and apparatus for electricalprinting and more particularly to a method and apparatus for electricalprinting utilizing an arrangement wherein a type member is pressedagainst a metal foil which is in engagement with a surface upon which itis desired to print, and an electrical current of short time duration ispassed through the type member and the foil.

The invention method and apparatus is especially adapted for use inengraving where it is desired to im-` utilize heated platens and variousarrangements of heating coils and the like for heating the type membersemployed therewith such that suitable heat is transferred to thematerial upon which it is desired to print.

and printing operations therewith are delayed due to the time requiredto heat up the platens or the type members. The use of known devices isalso inconvenient in cases where it is desired to change the typemembers frequently since the type members and platen must be allowedtime to cool after printing` before the type may be changed.

In the present invention, `an electrical current of short time durationis passed through atype member and a metal foil which is in engagementwith a surface upon which it is desired to print, the current generatingSullicient heat to soften the surface and permit the faccvof the typemember to be pressed thereinto. Since. the heat is generated veryrapidly,` the engraving 'operation may be carried out without thenecessity of waiting for the platens or the type members to be preheatedas in prior art devices. Furthermore, since the heat is generated sorapidly, the platens and the typemembers employed in the presentinvention do not have an opportunity to heat up to any great extent, andthe type members may be changed immediately without waiting for them tocool to a lower temperature.

An object of the present invention is the provision of a new and novelmethod and apparatus for electrical printing wherein it is not necessaryto preheat the platens or type members utilized therein.

Another object is to provide a new and novel method and apparatus forelectrical printing wherein the platens and type members utilizedtherein are not heated to anygreat extent during printing operations.

A further object of the invention is the provision of a new and novelmethod and apparatusl for `electrical Such devices are complicated andexpensive in construction ICC 2 printing which is simple andinexpensive, yet ecient and reliable in operation.

Other objects and many of the attendant' advantages of this inventionwill be readily appreciated as the same becomes better understood byreference to the following detailed description when considered inconnection with the accompanying drawing wherein:

Fig. 1 is a schematic View of a printing apparatus according to theinvention;

Fig. 2 is a somewhat schematic plan view of a printing arrangementaccording to the invention, and

Fig. 3 is a cross-sectional view of a modification of the type holdersshown in Fig. 2.

Referring now to the drawings, wherein like reference charactersdesignate like or corresponding parts throughout `the several views,there is shown in Fig. 1 a member 10 having an upper surface 11 uponwhich it is desired to print. Member 10 may be formed preferably of aexible material such as leather or a thermoplastic and the like and isheld in place by a Vsuitable clamping means (not shown).

A" metal foil 12 is disposed in frictional engagement with surface 11and may be formed of any suitable metal such as aluminum, copper and thelike, the foil being on the order of .001 to .005 inch in thickness. Aterminal 13 issecured to the outer periphery of the foil and thecontactingy surface between the terminal and the foil is preferably offairly large area to prevent excessive heat from being generated in thefoil adjacent the terminal.

A type member 14 formed of brass or type metal and the like has a faceportion 15 upon which a suitable character is formed. Any suitable means(not shown) may be provided for applying pressure to member 14 as forexample utilizing a conventional press arrangement or by mounting thetype member in a manually operated stampy assembly and the like. Theamount of pressure required will vary according to the size of the typemember and the type of material of which member 10 is composed. lfmember lil is formed of a material the softening temperature of whichdecreases with pressure, it may be desirable to increase the pressure onmember 14, thereby decreasing the amount of heat which it is necessaryto develop and consequently decrease the amount of current or the timeduration of the current which passes through members 11 and 14. However,if the pressure applied to member 14 is increased to a sufiicientdegree, the contact resistance between the face portion of the typemember and the metal foil may be decreased to a point where the metalfoil will melt at the edges of the face portion before suicient heat isgenerated to soften surface 11 and permit the character formed on thetype member to be impressed therein. Such melting of the foil isundesirable, and may be avoided either by applying less pressure to thetype member or by coating the upper surface of the foil with anelectrical semi-conductor such as graphite or the like, therebyincreasing the contact resistance between the type and the foil.

A terminal 16 is suitably secured to member 14 and the terminal isconnected by a lead 17 to one pole of a source of electrical energy suchas battery 18 or the like. Terminal 13 is connected to the opposite poleof the battery through the intermediary of lead 19 and switch 20. It isapparent that by actuating switch 20, the flow of current throughmembers 11 and 14 may be selectively controlled.

The operation of the apparatus shown in Fig. 1 is as follows:

Foil 12 is initially placed in frictional engagement with surface 11 ofmember 10 and member 14 is pressed downwardly against foil 12 bysuitable means as pre- Patented Nov. 4, laas' viously described. Thefoil and the type member are connected in the electrical circuit asshown, and switch Ztl is closed for a predetermined short time duration.The current which ows through members 14 and 11 when switch 20 is closedgenerates heat in surface 11 immediately under face portion 15 and thematerial of member softens at that point sufdciently to allow portion tobe pressed into surface 11, `thereby engraving the character which isformed on portionv 15 into surface 11. However, since the current flowsfor only a short period of time, the type member and the foil do notheat up to any appreciable extent except .immediately adjacent theportions of members 11 and 14 which are in Contact with one another. Theremaining portions of members 11 and 14 remain relatively cool andtherefore these members may be changed immediately without allowing themtime to cool after a printing operation.

In the arrangement shown in Fig. 2, a sheet of metal foil is positionedin frictional engagement with a surface upon which it is desired toprint, the surface being immediately below the foil and hidden thereby.Two elongated type holders 26 each have cavities 27 formed therein, anda plurality of type members 28 are positoned in the cavities, the typemembers being rigidly clamped in place by means of adjustable clampingscrews 29 threaded in end walls 30 of members 26. The face portions ofthe type members are in contact with foil 25 and a suitable means (notshown) is provided for' applying pressure to the type members asdescribed in connection with the apparatus shown in Fig. l. Terminals 31are secured to the type holders, and lead 17 corresponds to lead 17shown in Fig. 1.

A plurality of elongated electrodes 32 are secured to member 25, theseelectrodes being substantially coextensive with members 26 and equallyspaced from the lateral portions thereof. Each -of members 32 isconnected through terminals 33 to lead 19 which corresponds with lead 19in Fig. l, whereby a current may be selectively passed through members26 and 32 in a manner similar to that described in connection with theapparatus shown in Fig. 1. Elongated electrodes 32 provide a meanswhereby the current flowing through the foil from the type members isdistributed, thereby preventing the foil from heating up as would be thecase if an electrode of f i members 26 shown in Fig. 2. A plurality oftype members 38, only one of which is shown, are positioned withincavity 36 and are clamped in place by a clamping screw similarto screws29 shown in Fig. 2. The type members t snugly within cavity 36 such thatthe outer surfaces of the type members are in engagement with the innersurfaces of the cavity, thereby providing a good electrical Contacttherebetween.

insulating members 40 are secured to surface 37 as by bonding or thelike and are longitudinally coextensive with cavity 36, being positionedadjacent thereto on either side thereof, as shown. Members 40 are formedof an electrically nonconductive material which is also resilient suchas rubber or the like. Electrodes 41 of the same size and configurationas members 4t) are secured thereto as by bonding or the like, theelectrodes `being formed of electrically conductive material such ascopper or the like. It should be noted that when type members 38 areclamped in place as shown, the lower surfaces 42 of the face portionsthereof are slightly higher than the lower surfaces 43 of electrodes 41.The ditference in Member has a rectanf CII height of surfaces 42 and 43may be on the order of .01 to .l inch, provided that when pressure. isapplied to the device, members 40 will yield suiciently to enablesurfaces 43 to be urged upwardly above surface 42. When the device isutilized for printing, pressure is applied in a downward direction,causing members 40 to be compressed and allowing surfaces 43 to moveupwardly suiciently such that surface 42 may be pressed into thesurfacer upon which it is desired to print.

A terminal 45 is secured to member 35 and is connected to lead 17 which.corresponds to lead 17 shown in Fig. 2. Terminals 46 which correspond toterminals 33 in Fig'. 2J are secured' to electrodes 41 which correspondto electrodes 32 in Fig. 2, terminals 46. being connected to lead 19which corresponds to lead 19 in Fig. 2.

It is apparent that when the device shown in Fig. 3 is connected in asuitable electrical circuit and the switch closed, current will flowthrough member 35, type members 38, `the foil inv engagement therewith,and through electrodes 41 which are also in engagement with the foil.

lt should be noted that in the apparatus shown in each of Figs. 1 3, ametal foil is placed in frictional engagement with a surface upon whichit is desired to print and the face portion. of a type member pressedagainst the foil by a suitable means. An electrical current of shorttime duration is thereupon passed through the type mem ber and the foil.such that the character formed on the type face .is impressed into saidsurface.

It is apparent from the foregoing that there is provided a method andapparatus wherein it is not necessary to preheat the `componentsutilized therein and the components are not heated to any great extentduring printing operations. .The method and apparatus is simple andinexpensive, yet efficient and reliable in operation.

It should be understood that the particular polarity of the electriccircuit of the device described herein, e. g. the embodiment shown inFig. l, is not essential. Thus, if desired, the positive terminal of thebattery in Fig. l can be connected to switch 20 with the negativeterminal of the battery connected to type member 14, linstead of asshown in Fig. 1. Further, either D. C. or A. C. electrical energy may heemployed in the invention device.

Obviously many modifications and variations of the present invention arepossible in the light of the above teachings. It is therefore to beunderstood that within the scope of the appended claims the inventionmay be practiced otherwise than as specifically described.

I claim:

V1. A method of electrical printing which comprises positioning a sheetof metal foil adjacent a surface upon which it is desired to print,pressing the face of a type member against said foil and passing anelectric current below arcing potential through said type face and saidmetal foil to heat the latter.

2. Av method of electrical printing which comprises coating one surfaceof a sheet of metal foil with an electrical semi-conductor, positioningthe opposite surface of said sheet adjacent a surface upon which it isdesired to print, pressing the face of a type member against said foiland passing an electrical current below arcing potentialth'rough saidtype face and said metal foil to heat the latter.

.3. A method of electrical printing which comprises positioning a sheetof metal foil in frictional engagementwith a surface upon which it isdesired to print, pressing the face of a type member against said foiland passing an electric current of short time duration and below arcingpotential through said `type face and said metal foil to heat thelatter.

l4. A method of electrical printing which comprises positioning a sheetof metal foil in frictional engagement with a surface upon which it isdesired to print. pressing the face of a type member against said foil,passing an electric current of short time duration and below arcingpotential through said type face and said metal foil to heat the latter,allowing said foil to cool and removing the excess foil from saidsurface.

5. Electrical printing apparatus which comprises a sheet of metal foilin engagement with a surface upon which it is desired to print, a typemember having a face portion formed thereon, said face portion being incontact with said foil, an electrical network including said type memberand said foil, a source of current below arcing potential for saidnetwork, and means for establishing a ow of current from said source insaid network so that the surface of said foil which is in contact withthe face portion of said type member may be selectively heated andthereby softened.

6. Electrical printing apparatus which comprises a sheet of metal foilin engagement with a surface upon which it is desired to print, a firstelectrical terminal secured to said foil, a type member composed ofelectrically conductive material and having a face portion formedthereon, said face portion being in frictional engagement with saidfoil, a second electrical terminal secured to said type member, anelectrical circuit connected to said two terminals, a source of currentbelow arcing potential for said circuit, and switch means forestablishing a flow of current from said source in said circuit so thatthe surface of said foil which is in contact with the face portion ofsaid type member may be selectively heated and thereby softened;

7. Electrical printing apparatus which comprises a sheet of metal foilin engagement with a surface upon which it is desired to print, aplurality of elongated electrical terminals connected to said foil, atleast one elongated type support member positioned adjacent saidplurality of electrical terminals and being substantially coextensivetherewith, a plurality of type members rigidly supported within saidtype support member and each having a face portion formed thereon, eachof said face portions being in frictional engagement with said foil, an

electrical terminal secured to said type support member, an electricalcircuit connected to said terminals, a source of current below arcingpotential for said circuit, and switch means for establishing a ow ofcurrent from said source in said circuit so that the surface of saidfoil which is in co-ntact with the face portion of said type member maybe selectively heated and thereby softened.

8. In an electrical printing apparatus, a type holder formed ofelectrically conductive material and having a cavity formed therein, atleast one type member positioned within said cavity and in frictionalengagement with said type holder, said type member having a face portionformed thereon, an electrically nonconductive member secured to saidtype holder adjacent the open end of said cavity, and an electricallyconductive member secured to said nonconductive member.

9. In an electrical printing apparatus, an elongated type holder formedof electrically conductive material and having a cavityformed in onesurface thereof, a first terminal secured to said type holder, aplurality of type members positioned within said cavity and infrictional engagement with said type holder, each of said type membershaving a face portion formed thereon, a plurality of electricallynonconductive members secured to said type holder adjacent the open endof said cavity, an electrically conductive member secured to each ofsaid nonconductive members, and a second terminal secured to each ofsaid electrically conductive members.

References Cited in the file of this patent UNITED STATES PATENTS1,865,610 Blair July 5, 1932 1,909,844 Brenner May 16, 1933 2,294,146Wise Aug. 25, 1942 2,479,375 Langer Aug. 16, 1949 2,662,045 Baggott Dec.8, 1953 2,711,781 Langer June 28, 1955

